Modification of Carbon Nanotubes for H2S Sorption

Multiwall carbon nanotubes (MWNTs), prepared with methane as carbon source through the chemical vapor deposition (CVD) method at 900 degrees C, were functionalized to have amino and amido functional groups and then deposited with tungsten (W) nanoparticles. Pure H2S sorption on MWNTs, MWNTs loaded with W, functionalized MWNTs, and activated carbon (prepared from walnut shell) was investigated at 20 degrees C and a pressure range of 1-10 bar. X-ray diffraction, transmission and scanning electron microscopies, Raman spectroscopy, ASAP, inductively coupled plasma, and temperature-programmed reduction analysis were performed to determine the properties of the sorbent. The presence of amino functional groups was found to increase the sorption capacity of MWNTs, while the decoration of MWNTs with W nanoparticles decreased the sorption capacity. Results of the research revealed that functionalized MWNTs have a higher H2S sorption capacity than activated carbon. Langmuir, Freundlich, Unilan, Sips, and Toth isotherm models were used for a mathematical description of hydrogen sulfide equilibrium adsorption, and the experimental data for all four adsorbents showed the best accordance with the Freundlich model, while the Unilan model had the least accordance with the experimental data obtained for adsorbents based on MWNTs.